The detection of certain biological molecules plays an important part in many aspects of life. For example, in the medical field, there is an ever-present need to detect bacterial or viral pathogens, or biological molecules. Other fields in which sensitive assays are essential include the food and beverage industries.
WO03/074731 discloses a method of probing for a nucleic acid. A nucleic acid solution is contacted with an oligonucleotide probe with an electrochemically active marker. The probe is caused to at least partially hybridise with any complementary target sequence which may be present in the nucleic acid solution. Following enzymatic degradation of the nucleic acid probe, information is electrochemically determined relating to the marker. Compounds for use in the method are also disclosed.
WO2005/005657 discloses a method of detecting protease activity in which a sample solution is contacted with a protease substrate with an electrochemically active marker, providing conditions under which any protease which may be present in the sample may degrade the protease substrate and information relating to the electrochemically active marker is electrochemically determined. Certain novel compounds for use in the process were also disclosed.
WO2012/085591 describes certain diferrocenyl compounds for use as electrochemical labels.
There is a continuing need to develop labels that enable detection of the presence in small concentrations of biological substrates or indicators, for example, nucleic acids (in isolated form or in the form of larger molecules, for example, natural or synthetic oligonucleotides), or amino acids (in isolated form or in the form of larger molecules, for example, natural or synthetic peptides). In particular, there is a continuing need for new labels with different oxidation potentials and/or with different chemical or physical properties thereby widening the range of possible assays available and increasing the scope for the development of multiplex reactions.